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The rapid re-endothelialization of the vascular stent surface is desirable for preventing thrombosis or reducing restenosis. Many biological factors that promote the biological behavior of endothelial cells have been used for the surface modification of stents. Vascular endothelial growth factor (VEGF), which plays an important role in angiogenesis, induces strong vascular growth. In this study, we investigated different VEGF concentrations (50 to 500 ng/ml) to determine the optimum concentration for biocompatibility. First, VEGF-loaded heparin/poly-l-lysine (Hep-PLL) nanoparticles were created by electrostatic interactions. Then, the VEGF-loaded nanoparticles were immobilized on dopamine-coated 316 L stainless steel (SS) surfaces. The physical and chemical properties of the modified surface were characterized and the biocompatibility was evaluated in vitro. The results indicated that the VEGF-loaded nanoparticles were immobilized successfully on the 316LSS surface, as evidenced by the results of Alcian Blue staining and water contact angle (WCA) measurements. The low platelet adhesion and activation indicated that the modified surfaces had good blood compatibility. The modified surfaces showed a good inhibitory effect on smooth muscle cells, indicating that they inhibited tissue hyperplasia. In addition, the modified surfaces significantly promoted endothelial cell adhesion, proliferation, migration, and biological activity, especially VEGF concentration was 350 ng/ml (NPV350). The optical VEGF concentration of the surface modified Hep-PLL nanoparticles was 350 ng/ml. The proposed method shows promise for potential applications for cardiovascular devices., (© 2020 Wiley Periodicals, Inc.)

The biocompatibility of currently used coronary artery stent is still far from perfect, which closely related to insufficient endothelialization and thrombus formation. In this study, heparin, fibronectin and VEGF were immobilized on Ti surface to construct a multifunctional microenvironment with favorable properties to inhibit thrombosis formation and promote endothelialization simultaneously. The microenvironment on Ti surface was characterized in detail and demonstrated that the Hep/Fn/VEGF biofunctional coating was constructed successfully on Ti surface. The influence of surface properties such as chemical composition, roughness, hydrophilicity, and binding density of biomolecules on the performances of hemocompatibility and cytocompatibility was evaluated and discussed. Modified surface significantly enhanced the AT III binding density and prolonged the clotting time. In vitro platelet adhesion and activation assays further proved that the modified surface presented favorable anti-coagulant property. In addition, the proliferation of endothelial progenitor cells (EPCs) and endothelial cells (ECs) on the Hep/Fn/VEGF biofunctional coating was significantly promoted. In conclusion, the Hep/Fn/VEGF biofunctional coating was successfully constructed with desirable anticoagulant and endothelialization supporting properties. This work may provide a promising approach for biofunctional surface modification of coronary artery stent to acquire a desired multifunctional microenvironment. [ABSTRACT FROM AUTHOR]